Errors keep showing up in Mailgun's logs: all callbacks to ~/mailgun/notify end up being undelivered. Might I be missing a configuration step in Odoo? <bountysource-plugin> --- Want to back this issue? **[Post a bounty on it!](https://www.bountysource.com/issues/63775123-10-0-mailgun-s-callback-to-mailgun-notify-returns-500?utm_campaign=plugin&utm_content=tracker%2F24901677&utm_medium=issues&utm_source=github)** We accept bounties via [Bountysource](https://www.bountysource.com/?utm_campaign=plugin&utm_content=tracker%2F24901677&utm_medium=issues&utm_source=github). </bountysource-plugin>